Are there disadvantages of modified atmosphere packaging (MAP) and how to they work? What are the regulations in the EU?

Modified atmosphere packaging (MAP) relies on altering the composition of gases in contact with the food by replacing air with a single gas or a mixture of gases. This is then combined with low temperature storage of less than 3 degrees. The aim of MAP is to exclude or greatly reduce oxygen levels, to retain the moisture content of the food and to inhibit aerobic microbial growth.

While this method of packaging works well to inhibit the growth of strict aerobic spoilage bacteria, many bacteria associated with foodborne illness, such as Clostridium spp., Campylobacter spp. and Listeria monocytogenes, are not affected to the same extent. Fortunately, there are other means to control these bacteria such as controlling the moisture levels and the pH of the food, as well as monitoring storage time and temperature.

The choice of packaging material depends on the recommended storage temperature for the food, the relative humidity of the package and the effect of light, if any, on the contents. Vacuum packaging and MAP are useful for high fat foods as they help prevent the fats becoming rancid by reducing the exposure to oxygen.

Since December 2004 a new EU framework regulation on food-contact materials is in effect. There exists an Opinion of the Scientific Committee on Food on the use of carbon monoxide as component of packaging gases in modified atmosphere packaging for fresh meat.

The Committee therefore concluded that there is no health concern associated with the use of 0.3%-0.5% CO in a gas mixture with CO2 and N2 as a modified atmosphere packaging gas for fresh meat provided the temperature during storage and transport does not exceed 4°C. However the Committee wishes to point out that, should products be stored under inappropriate conditions, the presence of CO may mask visual evidence of spoilage.

Opinion of the Scientific Committee on Food

• europa.eu.int/comm/food/fs/sc/scf/out112_en.pdf
• Article “EU Framework regulation on food-contact materials now in effect”:
  http://www.packaginglaw.com/index_news.cfm?ID=179

To see the full text of the 14-page published version of the regulation in the Official Journal of the European Union:
europa.eu.int/eur-lex/lex/LexUriServ/ site/en/oj/2004/l_338/l_33820041113en00040017.pdf